Why is the modified Fibonacci sequence used when estimating?

The modified Fibonacci sequence is a series of numbers that starts with 0, 1, 2, 3, 5, 8, 13, 20, 40, 100, and so on. It is used when estimating the relative size and complexity of backlog items, such as stories and features, using story points or normalized estimation. The modified Fibonacci sequence reflects the uncertainty in estimating larger items, as the gap between the numbers increases as the numbers get bigger. This means that the larger the item, the less precise the estimate, and the more likely it is to be split into smaller items. The modified Fibonacci sequence also helps to avoid the false sense of accuracy that comes from using linear scales, such as hours or days, which may not account for the variability and unpredictability of the work. References: Exam Study Guide: SP (6.0) - SAFe® Practitioner, Story, Feature, Estimating